ASL originated in the early 19th century in the American School for the Deaf (ASD) in Hartford, Connecticut, from a situation of language contact. Since then, ASL use has propagated widely via schools for the deaf and deaf community organizations. Despite its wide use, no accurate count of ASL users has been taken, though reliable estimates for American ASL users range from 250,000 to 500,000 persons, including a number of children of deaf adults. ASL users face stigma due to beliefs in the superiority of spoken language to signed language, compounded by the fact that ASL is often glossed in English due to the lack of a standard writing system.

ASL signs have a number of phonemic components, including movement of the face and torso as well as the hands. ASL is not a form of pantomime, but iconicity does play a larger role in ASL than in spoken languages. English loan words are often borrowed through fingerspelling, although ASL grammar is unrelated to that of English. ASL has verbal agreement and aspectual marking, and has a productive system of forming agglutinative classifiers. Many linguists believe ASL to be a subject-verb-object (SVO) language, but there are several alternative proposals to account for ASL word order.

The influence of FSL on ASL is readily apparent; for example, it has been found that about 58% of signs in modern ASL are cognate to Old French Sign Language signs.[4][6] However, this is far less than the standard 80% measure used to determine whether related languages are actually dialects.[6] This suggests that nascent ASL was highly affected by the other signing systems brought by the ASD students, despite the fact that the school's original director Laurent Clerc taught in FSL.[4][6] In fact, Clerc reported that he often learned the students' signs rather than conveying FSL:[6]

I see, however, and I say it with regret, that any efforts that we have made or may still be making, to do better than, we have inadvertently fallen somewhat back of Abbé de l’Épée. Some of us have learned and still learn signs from uneducated pupils, instead of learning them from well instructed and experienced teachers.

—Clerc, 1852, from Woodward 1978:336

It has been proposed that ASL is a creole with FSL as the superstrate language and with the native village sign languages as substrate languages.[7] However, more recent research has shown that modern ASL does not share many of the structural features that characterize creole languages.[8] ASL may have begun as a creole and then undergone structural change over time, but it is also possible that it was never a creole-type language.[8] There are modality-specific reasons that sign languages tend towards agglutination, for example the ability to simultaneously convey information via the face, head, torso, and other body parts. This might override creole characteristics such as the tendency towards isolating morphology.[9] Additionally, Clerc and Gallaudet may have used an artificially constructed form of manually coded language in instruction rather than true FSL.[10]

Although the United States, the United Kingdom, and Australia share English as a common oral and written language, ASL is not mutually intelligible with British Sign Language (BSL) or Auslan.[11] All three languages show degrees of borrowing from English, but this alone is not sufficient for cross-language comprehension.[11] It has been found that a relatively high percentage (37–44%) of ASL signs have similar translations in Auslan, which for oral languages would suggest that they belong to the same language family.[12] However, this does not seem justified historically for ASL and Auslan, and it is likely that this resemblance is due to the higher degree of iconicity in signed languages in general, as well as contact with English.[13]

Prior to the birth of ASL, signed language had been used by various communities in the United States.[14] In the United States, as elsewhere in the world, hearing families with deaf children have historically employed ad-hoc home sign, which often reaches much higher levels of sophistication than gestures used by hearing people in spoken conversation.[14] As early as 1541 at first contact by Francisco Vásquez de Coronado, there were reports that the Plains Indians had developed a sign language to communicate between tribes of different languages.[15]

The largest group of students during the first seven decades of the school were from Martha’s Vineyard, and they brought MVSL with them.[21] There were also 44 students from around Henniker, New Hampshire, and 27 from the Sandy River valley in Maine, each of which had their own village sign language.[5][nb 3] Other students brought knowledge of their own home signs.[5]Laurent Clerc, the first teacher at ASD, taught using French Sign Language (FSL), which itself had developed in the Parisian school for the deaf established in 1755.[4] From this situation of language contact, a new language emerged, now known as ASL.[4]

More schools for the deaf were founded after ASD, and knowledge of ASL spread to these schools.[4] In addition, the rise of deaf community organizations bolstered the continued use of ASL.[22] Societies such as the National Association of the Deaf and the National Fraternal Society of the Deaf held national conventions that attracted signers from across the country.[23] This all contributed to ASL's wide use over a large geographical area, atypical for a signed language.[6][24]

Up to the 1950s, the predominant method in deaf education was oralism – acquiring oral language comprehension and production.[25] Linguists did not consider signed language to be true "language", but rather something inferior.[25] Recognition of the legitimacy of ASL was achieved by William Stokoe, a linguist who arrived at Gallaudet University in 1955 when this was still the dominant assumption.[25] Aided by the civil rights movement of the 1960s, Stokoe argued for manualism, the use of sign language in deaf education.[25][26] Stokoe noted that signed language shares the important features that oral languages have as a means of communication, and even devised a transcription system for ASL.[25] In doing so, Stokoe revolutionized both deaf education and linguistics.[25] In the 1960s, ASL was sometimes referred to as "Ameslan", but this term is now considered obsolete.[27]

Counting the number of ASL speakers is difficult because ASL users have never been counted by the American census.[28][nb 4] The ultimate source for current estimates of the number of ASL users in the United States is a report for the National Census of the Deaf Population (NCDP) by Schein and Delk (1974).[29] Based on a 1972 survey of the NCDP, Schein and Delk provided estimates consistent with a signing population between 250,000 and 500,000.[1] The survey did not distinguish between ASL and other forms of signing; in fact, the name "ASL" was not yet in widespread use.[30]

Incorrect figures are sometimes cited for the population of ASL speakers in the United States based on misunderstandings of known statistics.[31] Demographics of the deaf population have been confused with those of ASL use, since adults who become deaf late in life rarely use ASL in the home.[32] This accounts for currently cited estimations which are greater than 500,000; such mistaken estimations can reach as high as 15,000,000.[33] A 100,000-person lower bound has been cited for ASL users; the source of this figure is unclear, but it may be an estimate of prelingual deafness, which is correlated with but not equivalent to signing.[34]

ASL is sometimes incorrectly cited as the third- or fourth-most-spoken language in the United States.[35] These figures misquote Schein and Delk (1974), who actually concluded that ASL speakers constituted the third-largest population requiring an interpreter in court.[35] Although this would make ASL the third-most used language among monolinguals other than English, it does not imply that it is the fourth-most-spoken language in the United States, since speakers of other languages may also speak English.[36]

ASL is used throughout Anglo-America.[24] This contrasts with Europe, where a variety of sign languages are used within the same continent.[24] The unique situation of ASL seems to have been caused by the proliferation of ASL through schools influenced by the American School for the Deaf, wherein ASL originated, and the rise of community organizations for the deaf.[37]

Variation in ASL is found throughout the United States and Canada.[42]

Just as there are accents in speech, there are regional accents in sign. People from the South sign slower than people in the North—even people from northern and southern Indiana have different styles.

—Walker, Lou Ann (1987). A Loss for Words: The Story of Deafness in a Family. New York: HarperPerennial. p. 31. ISBN0-06-091425-4.

Mutual intelligibility among these ASL varieties is high, and the variation is primarily lexical.[42] For example, there are three different words for English about in Canadian ASL; the standard way, and two regional variations (Atlantic and Ontario), as shown in the videos on the right.[43] Variation may also be phonological, meaning that the same sign may be signed in a different way depending on the region. For example, an extremely common type of variation is between the handshapes /1/, /L/, and /5/ in signs with one handshape.[44]

There is also a distinct variety of ASL used by the Black deaf community.[42] Black ASL evolved as a result of racially segregated schools in some states, which included the residential schools for the deaf.[45] Black ASL differs from standard ASL in vocabulary, phonology, and some grammatical structure.[42][45] While African American Vernacular English (AAVE) is generally viewed as more innovating than standard English, Black ASL is more conservative than standard ASL, preserving older forms of many signs.[45] Black sign language speakers use more two-handed signs than in mainstream ASL, are less likely to show assimilatory lowering of signs produced on the forehead (e.g. KNOW), and use a wider signing space.[45] Modern Black ASL borrows a number of idioms from AAVE; for instance, the AAVE idiom "I feel you" is calqued into Black ASL.[46]

ASL is used internationally as a lingua franca, and a number of closely related sign languages derived from ASL are used in many different countries.[42] Even so, there have been varying degrees of divergence from standard ASL in these imported ASL varieties. Bolivian Sign Language is reported to be a dialect of ASL, no more divergent than other acknowledged dialects.[47] on the other hand, it is also known that some imported ASL varieties have diverged to the extent of being separate languages. For example, Malaysian Sign Language, which has ASL origins, is no longer mutually comprehensible with ASL and must be considered its own language.[48] For some imported ASL varieties, such as those used in West Africa, it is still an open question how similar they are to American ASL.[40]

When communicating with hearing English speakers, ASL-speakers often use what is commonly called Pidgin Signed English (PSE) or 'contact signing', a blend of English structure with ASL.[42][49] Various types of PSE exist, ranging from highly English-influenced PSE (practically relexified English), to PSE which is quite close to ASL lexically and grammatically, but may alter some subtle features of ASL grammar.[49] Fingerspelling may be used more often in PSE than it is normally used in ASL.[50] There have been some constructed sign languages, known as Manually Coded English (MCE), which match English grammar exactly and simply replace spoken words with signs; these systems are not considered to be varieties of ASL.[42][49]

Tactile ASL (TASL) is a variety of ASL used throughout the United States by and with the deaf-blind.[42] It is particularly common among those with Usher's syndrome, found especially in Louisiana and Seattle.[42] This syndrome results in deafness from birth followed by loss of vision later in life; consequently, those with Usher's syndrome often grow up in the deaf community using ASL, and later transition to TASL.[51] TASL differs from ASL in that signs are produced by touching the palms, and there are some grammatical differences from standard ASL in order to compensate for the lack of non-manual signing.[42]

The majority of children born to deaf parents are hearing.[52] These children, known as CODAs ("Children Of Deaf Adults") are often more culturally deaf than deaf children, the majority of whom are born to hearing parents.[52] Unlike many deaf children, CODAs acquire ASL as well as deaf cultural values and behaviors from birth.[52] These bilingual hearing children may be mistakenly labeled as being "slow learners" or as having "language difficulties" due to preferential attitudes towards spoken language.[53]

Although there is no well-established writing system for ASL,[54] written sign language dates back almost two centuries. The first systematic writing system for a sign language seems to be that of Roch-Ambroise Auguste Bébian, developed in 1825.[55] However, written sign language remained marginal among the public.[56] In the 1960s linguist William Stokoe created Stokoe notation specifically for ASL. It is alphabetic, with a letter or diacritic for every phonemic (distinctive) hand shape, orientation, motion, and position, though it lacks any representation of facial expression, and is better suited for individual words than for extended passages of text.[57] Stokoe used this system for his 1965 A Dictionary of American Sign Language on Linguistic Principles.[58]

The first writing system to gain use among the public was SignWriting, proposed in 1974 by Valerie Sutton.[56] SignWriting consists of more than 5000 distinct iconic graphs/glyphs.[56] Currently it is in use in many schools for the Deaf, particularly in Brazil, and has been used in international sign language forums with speakers and researchers in more than 40 countries, including Brazil, Ethiopia, France, Germany, Italy, Portugal, Saudi Arabia, Slovenia, Tunisia, and the United States. Sutton SignWriting has both a printed and an electronically produced form so that persons can use the system anywhere that oral languages are written (personal letters, newspapers and media, academic research). The systematic examination of the International Sign Writing Alphabet (ISWA) as an equivalent usage structure to the International Phonetic Alphabet for spoken languages has been proposed.[59] According to some researchers, SignWriting is not a phonemic orthography, and does not have a one-to-one map from phonological forms to written forms.[60] This assertion has been disputed and the process for each country to look at the ISWA and create a phonemic/morphemic assignment of features of each sign language was proposed by researchers Msc. Roberto Cesar Reis da Costa and Madson Barreto in a thesis forum on June 23, 2014.[61] At this point the Wikimedia has accepted SignWriting for inclusion in a translation project of articles written in English and then translated into ASL and is working on a specific translation engine.[62]

The most widely used transcription system among academics is HamNoSys, developed at the University of Hamburg.[63] Based on Stokoe Notation, HamNoSys was expanded to about 200 graphs in order to allow transcription of any sign language.[63] Phonological features are usually indicated with single symbols, though the group of features that make up a handshape is indicated collectively with a symbol.[63]

Comparison of ASL writing systems. Sutton SignWriting is on the left, followed by Si5s, then Stokoe notation in the center, with SignFont and its simplified derivation ASL-phabet on the right.

Several additional candidates for written ASL have appeared over the years, including SignFont, ASL-phabet, and Si5s.

For English-speaking audiences, ASL is often glossed using English words. These glosses are typically all-capitalized and are arranged in ASL order. For example, the ASL sentence DOG NOW CHASE>IX=3 CAT, meaning "the dog is chasing the cat", uses NOW to mark ASL progressive aspect and shows ASL verbal inflection for the third person (written with >IX=3). However, glossing is not used to write the language for speakers of ASL.[54]

Each sign in ASL is composed of a number of distinctive components. A sign may use one hand or both. Each hand assumes a handshape with a particular orientation in a particular location on the body or in the "signing space", and may involve movement.[65] Changing any one of these may change the meaning of a sign, as illustrated by the ASL signs THINK and DISAPPOINTED:

ASL has a rich system of verbal inflection. This involves both grammatical aspect—how the action of verbs flows in time—and agreement marking.[71] Aspect can be marked by changing the manner of movement of the verb; for example, continuous aspect is marked by incorporating rhythmic, circular movement, while punctual aspect is achieved by modifying the sign so that it has a stationary hand position.[71] Verbs may agree with both the subject and the object, and are marked for number and reciprocity.[72] Reciprocity is indicated by using two one-handed signs; for example, the sign SHOOT, made with an L-shaped handshape with inward movement of the thumb, inflects to SHOOT[reciprocal], articulated by having two L-shaped hands "shooting" at each other.[73]

ASL has a productive system of classifiers, which are used to classify objects and their movement in space.[74] For example, a rabbit running downhill would use a classifier consisting of a bent V classifier handshape with a downhill-directed path; if the rabbit is hopping, the path is executed with a bouncy manner.[74] In general, classifiers are composed of a "classifier handshape" bound to a "movement root".[74] The classifier handshape represents the object as a whole, incorporating such attributes as surface, depth, and shape, and is usually very iconic.[75] The movement root consists of a path, a direction and a manner.[74]

The American manual alphabet. Letters with asterisks are shown from the side (*L left or *R right), rather than as the viewer would see them.

ASL possesses a set of 26 signs known as the American manual alphabet, which can be used to spell out words from the English language.[76] These signs make use of the 19 handshapes of ASL. For example, the signs for 'p' and 'k' use the same handshape but different orientations. A common misconception is that ASL consists only of fingerspelling; although such a method (Rochester Method) has been used, it is not ASL.[50]

Fingerspelling is a form of borrowing, a linguistic process wherein words from one language are incorporated into another.[50] In ASL, fingerspelling is used for proper nouns and for technical terms with no native ASL equivalent.[50] There are also some other loan words which are fingerspelled, either very short English words or abbreviations of longer English words, e.g. O-N from English 'on', and A-P-T from English 'apartment'.[50] Fingerspelling may also be used to emphasize a word that would normally be signed otherwise.[50]

The basic word order of ASL is disputed. Most linguists agree that ASL is a subject-verb-object (SVO) language with various phenomena affecting this basic word order.[77] Basic SVO sentences are signed without any pauses:[78]

However, other word orders may also occur, as ASL allows the topic of a sentence to be moved to sentence-initial position, a phenomenon known as topicalization.[79] In object-subject-verb (OSV) sentences, the object is topicalized, marked by a forward head-tilt and a pause:[80]

Even more word orders can be obtained through the phenomenon of subject copy. In subject copy, the subject is repeated at the end of the sentence, accompanied by head nodding, either for clarification or emphasis:[78]

ASL also allows null subject sentences, where the subject is implied rather than stated explicitly. Subjects can be copied even in a null subject sentence, in which the subject is omitted from its original position, yielding a verb-object-subject (VOS) construction:[80]

These properties of ASL allow it a variety of word orders, leading many to question which is the true, underlying, “basic” order. There are several other proposals that attempt to account for the flexibility of word order in ASL. One proposal is that languages like ASL are best described with a topic–comment structure, where words are ordered by their importance in the sentence rather than by their syntactic properties.[81] Another hypothesis is that ASL exhibits free word order, in which syntax is not encoded in word order whatsoever, but can be encoded by other means (e.g. head nods, eyebrow movement, body position).[77]

A common misconception is that signs are iconically self-explanatory, that they are a transparent imitation of what they mean, or even that they are pantomime.[82] In fact, many signs bear no resemblance to their referent, either because they were originally arbitrary symbols or because their iconicity has been obscured over time.[82] Even so, in ASL iconicity plays a significant role; a high percentage of signs resemble their referents in some way.[83] This is due to the fact that the medium of signed language—space—naturally allows more iconicity than oral language.[82]

In the era of the influential linguist Ferdinand de Saussure, it was assumed that the mapping between form and meaning in language must be completely arbitrary.[83] Although onomatopoeia is a clear exception, since words like 'choo-choo' bear clear resemblance to the sounds that they mimic, the Saussurean approach was to treat these as marginal exceptions.[84] ASL, with its significant inventory of iconic signs, directly challenges this theory.[85]

Research on acquisition of pronouns in ASL has shown that children do not always take advantage of the iconic properties of signs when interpreting their meaning.[citation needed] It has been found that when children acquire the pronoun ‘you’, the iconicity of the point (at the child) is often confused, being treated more like a name.[86] This is a similar finding to research in oral languages on pronoun acquisition. It has also been found that iconicity of signs does not affect immediate memory and recall; less iconic signs are remembered just as well as highly iconic signs.[87]

^The AbbéCharles-Michel de l'Épée, founder of the Parisian school Institut National de Jeunes Sourds de Paris, was the first to acknowledge that sign language could be used to educate the deaf. An oft-repeated folk tale states that while visiting a parishioner, Épee met two deaf daughters conversing with each other using FSL. The mother explained that her daughters were being educated privately by means of pictures. Épée is said to have been inspired by these deaf children when he established the first educational institution for the deaf. See:

Ruben, Robert J. (2005). "Sign language: Its history and contribution to the understanding of the biological nature of language". Acta Oto-laryngologica125 (5): 464–7. doi:10.1080/00016480510026287. PMID16092534.

^Whereas deafness was genetically recessive on Martha's Vineyard, it was dominant in Henniker. On the one hand, this dominance likely aided the development of sign language in Henniker since families would be more likely to have the critical mass of deaf people necessary for the propagation of signing. On the other hand, in Martha's Vineyard the deaf were more likely to have more hearing relatives, which may have fostered a sense of shared identity that led to more inter-group communication than in Henniker. See Lane, Pillard & French (2000:39).

^Although some surveys of smaller scope measure ASL use, such as the California Department of Education recording ASL use in the home when children begin school, ASL use in the general American population has not been directly measured. See Mitchell et al. (2006:1).

^Stokoe himself termed these cheremes, but other linguists have referred to them as phonemes. See Bahan (1996:11).

^a Sign-language names reflect the region of origin. Natural sign languages are not related to the spoken language used in the same region. For example, French Sign Language originated in France, but is not related to French.